Driving mechanism



E. B. N'owoslLsKl Sept. 18, 1934. l

' DRIVING MECHANI SM Filed Feb. 27. 1932 Patented Sept. 18, 1934 UNITED STA DRIVING MEcnANlsM Edward B. Nowoselski, Bloomfield, N. J., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application February 27, 1932, Serial No. 595,545A

13 Claims.

This invention relates to driving mechanism, Fig. 4 is a top sectional plan taken along the and particularly to driving mechanism of the impulse type, used to actuate engine magnetos and other units wherein intermittent accelerated movements are desirable.

An object of the invention is to provide novel means, releasable either manually or automatically yieldably holding the impulse controlling element of the driving mechanism in the inoperative position.

lAnother object is to provide an impulse controlling element s o constituted and controlled' that it tends constantly to move toward operative position, and in fact elfects such a movement independently of any rotating element of the mechanism, in response to either manual or automatic release of the holding means above described.

A further object is to provide novel means, actuated upon acceleration of the rotating mechanism to release said holding means, said releasing means being entirely independent of the impulse controlling elements.

Another object is to provide novel speed responsive means for positively preventing a return of the impulse controlling element to operative position during relatively high speed operation of the driving mechanism, even though the hold- ,ing means should, during such period, be accidentally or manually released. This feature of the invention, the incorporation of which is optional, preferably includes a plurality of radially swinging centrifugal elements movable toward said impulse controlling element to block the path which the said element tends to follow in its effort to reach `its operative position.

These and other objects and advantages to be derived from the use of the invention herein disclosed will become apparent upon an inspection of the following specification and the accompanying drawing, wherein the preferred embodiment of the invention is disclosed. It is to be understood, however, that the drawing is for the purpose of illustration only and not designed as a definition of the limits of the invention, reference being had for such purpose to the appended claims;

In the drawing,

Fig. 1 is a front View with certain parts in section showing the impulse controlling element in the operative position;

2 is a vertical section taken on line 2--2 of Fig. 1;

line 4 4 of Fig. 1;

Fig. 5 is a sectional view showing the optional feature above referred to; and

Fig. 6 is a reduced scale perspective of certain 66 of the parts.

In the drawing, the invention is shown applied to a magneto, the casing of which is indicated at 1 and the armature shaft at 2, said shaft being provided with a tapered portion 3, a key 4 and a 65 suitable nut 8 for rigidly securing thereto the hub 5 of the driven member 6 of the coupling, said member 6 being shown in the form of a cup or drum, rotatable within the casing 7 and adapted to receive intermittent impulsive movements during the initial period of operation of the associated engine; the drive being transmitted by way of a suitable driving connection (not shown) adapted to operatively engage coupling teeth or jaws 10 and 11 extending from the surface of the 75 driving member 12 of the coupling. As shown, the driving member 12 has a hub 13 fitting freely over the hub 5 of the driven member 6; the driving connection between the two being constituted by a pair of spirally wound springs 15 80 and 15a, separated by a dividing wall or partition 16 rotatable with drum, 6, the inner or driving ends of the springs being held fast to a slotted sleeve 18, as indicated at 19 and 20 in Fig. 3. The sleeve 18 is welded or otherwise suitably held fast 85 to the outer surface of the hub 13, the latter being longitudinally grooved, as indicated at 21 and 22, respectively, inr Fig. 3, to facilitate insertion or removal of the springs 15 and 15a. The inner periphery of the drum 6 is correspondingly 90 grooved, as indicated at 23 and 24, to facilitate insertion and removal of the outer ends of the springs, the said outer ends being turned back and held to the rounded edges of anchor members 26 secured by suitable means 27 to the cyln- 95 drical portion of the drum 6 atdiametrically op` posed points. Because of this relative positioning of the corresponding ends of the two springs, the driving strain is distributed on both sides of the coupling, rather than being conned to one side. As a result, the drive is smoother and the possibility of breakage of the springs is minimized. In order to hold the partition 16 fast with the drum 6, the said partition projects into the recesses 24 in the drum 6, as shown at 36.

-On the outer surface of the drum 6 there is v provided a pair of y longitudinallyextending notches 29 having abrupt sides 30 adapted to be engaged by the correspondingly shaped end of an impulse controlling element, constituting part .11G

of the novel combination yet to be described; while at diametrically opposed points on the outer periphery of theV driving member 12 there is provided a pair of outwardly extending cam surfaces having abrupt sides 32 and sloping sides 33, the latter'being adapted to periodically raise the impulse controlling mechanism out of engagement with the notches 29 to permit impulsive actuation of the drum 6 in response to the snap action of the. springs 15 andl5a.

The novel impulse' controlling mechanism and the novel yieldable holding means therefor preferably comprises a bifurcated pawl 40 having a pair of pointed edges 41 adapted to engage successively the abrupt faces 30 of the notches 29. The pawl is constantly urged towarctsuch notches by the action of a torsion spring 43 one end of which is secured to a fixed point 25 on the housing, the other eind frictionally engaging the upper surface of one of the free ends of the pawl; the integral ends being oscillatably mounted on a shaft 44 extendingfrom a mounting plate 45 attached to the casing 7 and constituting part of the coupling enclosure. When swung outwardly from the drum 6, one of the two teeth,41 of the pawl 40 is engaged by the noseY 46 of a yieldable holding element 47, herein shown as a plunger having at its outer end a lug 48 serving for the connection of a manually operable link (not shown). The central portion of the plunger has disposed thereon a compression spring 49 one end of which abuts a seat 50 in recess 51 of the housing 7, and the other end of which bears againsta collar 52 adjacent the nose 46; the spring thus acting to normally hold the collar 52 against the bracket 54 secured to the mounting plate 45 as indicated at 56. With this construction it is apparent that upon exertion of an outward pull, manually, on the plunger 47, the nose 46 will be freed from restraining engagement Ywith the edge 41 of the pawl 40, allowing the latter to swing inwardly toward the drum under the urge of the spring 43.

The novelty of the invention further resides in the provisionof means for automatically withdrawing the holding element 47 from restraining engagement with pawl 40, and as embodied herein such means includes an element 59 having a cam surface 60 adapted to engage the nose 46 of the holding element 47 and press the latter outwardly away from pawl 40, thus allowing the setting of the pawl 40 by the action of the spring 43. The cam 59 is normally in the position indicated in Fig. 1, to which position it is biased by the 'provision of a torsion spring 62 similar to the spring 43, but acting in an opposite direction.

The means for swinging the cam out of this normal position includes a lever 64 having a toe 65 at itsouter end and pivoted near such outer end to the drum 6 by the provisionY of a suitable pivot pin 67 (Fig. 3), the inner end of the lever having a non-magnetic roller 69 mounted thereon for engagement with the surface of the sleeve Y18 during low speed operation of th coupling, but movable from such position in response to centrifugal force as the coupling accelerates. Thus during normal operation of the engine, the lever remains in the position indicated in dash lines in Fig. 3, in` which position the nose 65 is'within the limits of the'idrum 6 and hence does not engage the depending portion 71 formed on the cam element 59.

The novel speed responsive means (the incorporation of which, as above noted, is optional) for positively preventing a return of the impulse governing element to engagement with the drum during relatively high speed rotation of the driving mechanism, even though the holding element 46 should be accidentally released, is shown in Fig. 5 as consisting of a pair of diametrically op. positely disposed centrifugal levers 75 which may, if employed, be pivotally mounted on either drum 6 or diaphragm 16 as indicated at 76, so as to swing outwardly under centrifugal action to produce a corresponding outward swinging of the arms 78 pivoted to the drum 6 as indicated at 79. As shown, the arms 78 have an outer contour corresponding'to the curvature of the drum, so that on outward movement they serve to close the. breaks in the peripheral surface ofthe drum, thus blocking the path which the pawl 40 follows in moving to its position of engagement with the abrupt faces 30. On deceleration of the coupling 6, 1evers275 return to the position indicated in Fig. 5, thus permitting a return of the pawl to the locking position in response to the action of the spring 43, as above described.

In operation, as the associated engine s turnedY over in the starting action, slow rotation is im- Y parted to the driving member 12, the initial stage of such rotation acting to wind the springs 15 and 100 15a, such winding action continuing until the cam surface 33 engages the pawl 40 tolraise the latter out of restraining contact with the drum 6. The springs 15 and 15a then become eiective to impart a swift rotary movement to the drum 6 105 and hence to the armature shaft 2, thus producing a more intensive spark for ignition purposes than could be produced by direct synchronous drive. As soon as the spring is unwound to the extent permitted before engagement of shoulder 'Y 32 with corresponding shoulder 34 on; the drum 6, its winding action again occurs by reason of the re-engagement of the pawl 40 with the oppositely disposed face 30 of the drum 6, after which the oppositely disposed cam surface 33 acts to again 115 eject the pawl and impart a second impulsive rotary movement to the armature shaft. When the speed of the coupling is increased suiciently, the correspondingly increased force of the ejecting'action ultimately throws the pawl 40 into a 12() position wherein it is caught and held by the nose 46 of the holding element 47. When thus caught and held, its Yreturn to drum engaging position (unless the plunger 47 should be manually Withdrawn), is impossible so long as the drum continues to rotate at normally high speed. With the use of the feature of the invention shown at Fig. 5, however, even an accidental withdrawal of plunger'47 would be of no consequence,

for such a return Yof the pawl is blocked by the VAs the associated engine'is brought to rest, the resulting deceleration of the coupling causes a retur of the lever 64 from the dash line position indicated in Fig. 3 to the position indicated in full 135 ployed) having in the meantime returned to the position indicated in Fig, 5.

Thus the pawl 40 is restored to its impulse con- "trolling position as an incident to the deceleration ofiA the engine, and is accordingly in proper posit/ionlto produce the desired restraining action when the engine is again started, and without the necessity of any manual intervention by the operator. In the event, however, of a failure of lever 64 to function properly, the operatorcan Withdraw the holding element 46 manually, by l5! meansof the connection (not shown) to the lug 48, as above described.

There is thus disclosed a mechanism which is capable of either manual or automatic operation, as desired, and which may be embodied in a compact and eicient assembly involving a relatively small number of parts in proportion to the functions performed. This economy of parts is especially pronounced in the embodiment shown in Figs. 1 4, inclusive, particularly when the feature shown in Fig. 5 is eliminated; and it may be omitted when not desired, although it is to be understood that this feature is of advantage and constitutes an important improvement in the art.

It is to be understood that the invention is not limited to magnetos or ignition devices in its application and that in its broader aspect, it possesses utility when applied to any mechanism wherein intermittent impulsive movement or alternative retarding and accelerating movements are desirable. It is to be understood that various other 'changes may be made in the form, details of construction, arrangement of the parts and the uses to which they are applied, without departing from the invention as deflned in the appended claims.

What is claimed is: l

1. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, normally rotating springs drivably connecting said members, a pawl engageable periodically with said driven member to hold the latter during storage of impulse producing energy in said springs, a latch engageablewith said pawl to normally hold the latter out of engagement with said driven member, a stationary shaft on which said pawl is pivotally mounted, and a second element oscillatable on said shaft independently of said pawl to withdraw said latch from the path of saidA pawl.

2. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, normally rotating resilient means drivably connecting said members, a pawl engageable periodically with said driven member 'to hold the latter during storage of limpulse producing energy in said resilient means, a latch engageable with said pawl to normally Ahold thelatter out 'of engagement with said driven member, a stationary shaft on which said pawl is mounted, a second element independently oscillatable on said shaft to withdraw said/latch from the path of said pawl, and means pivotally mounted on said driven member for actuating said second element.

3. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, normally rotating springs drivably connecting said members, a pawl engageable periodically with said driven member to hold the latter during storage of impulse producing energy in said springs, a latch engageable with said pawl to normally hold the latter out of engagement with said driven member, and means movable independently of said pawl for disengaging said latch, said means being responsive to deceleration of said driven member.

4. In a device of the class described, a' driving member, almember adapted to be driven either impulsively or synchronously with said driving member, normally rotating springs drivably connecting said members, a `pawl engageable periodically with said driven member to hold the latter during storage of impulse producing energy in said springs, a latch engageable with said pawl to normally hold the latter out of engagement with said driven member, means movable independently of said pawl for disengaging said latch, said means being responsive to deceleration of said driven member, and means mounted adjacent said pawl for thereupon causing its return to engagement with said driven member.

5. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, a normallyv rotating spring drivably connecting said members, a pawl engageable periodically withsaid driven memberto hold l,the latter during storage of impulse producing energy in said spring, a latch engageable with said pawl to normally hold the latter outof engagement with said driven member, and rotatable speed responsive means independent of said pawl for removing said latch from the path of said pawl.

6. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, a normally rotating spring drivably connecting said members, a pawl engageable periodically lwith said driven member to hold the latter during storage of impulse producing energy in said spring, a latch engageable with said pawl to normally hold the latter out of engagement with said driven member, means including a cam engageable with said latch for withdrawing the latter from the path of said pawl, and common mounting means for said cam and pawl.

7. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, a normally rotating spring drivably connecting said members, a pawl engageable periodically with said driven member to hold the latter during storage of impulse producing 'energy in said spring, a latch engageable with said pawl to normally hold the latter out of, engagement with said driven member, and means for thereafter blocking the return of said pawl into operative engagement with said driven member even though said latch should be withdrawn, until the speed of the driven member falls considerably below normal.

8. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, a normally rotating spring drivably connecting said members, a pawl engageable periodically with said d'riven member to hold the latter during storage of impulse producing energy in said spring, a latch engageable with said pawl to normally hold the latter out of engagement with said driven member, means for withdrawing said latch, said means being responsive to deceleration of said driven member, and additional means independent of said driving and driven members for promptly re-setting said latch following operation of said withdrawing means.

9. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, a normally rotating spring drivably connecting said members, a pawl engageable periodically with said driven member to hold the latter during storage of impulse producing energy in said spring, a spring-pressed plunger engageable with said pawl to normally hold the latter out of engagement with said driven member, and

means for repelling said plunger, said means independent of said pawl being responsive to decally with said driven member to hold thelatter during storage of impulse producing energy in said spring, and means movable through an arc of limited extent for thereafter blocking the return of said pawl into operative engagement kwith. said driven member until the speed of the driven member falls considerably below normal.

1l. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, a normally rotating spring drivably connecting said members, a pawl engageable periodically with said driven member to hold the latter during storage of impulse producing energy in said spring, a latch engageable with said pawl to normally hold the latter out of engagement with said driven member, and means for withdrawing said latch in response to deceleration of said driven member, said means including a cam mountedl adjacent said pawl.

12. In a device of the class described, a driving member, a member adapted to be driven either impulsively or synchronously with said driving member, 'a normally rotating spring drivably connecting said members, a pawl engageable periodically with said driven member to hold the latter during storage of impulse producing energy in said spring, a latch engageable with said pawl to normally hold the Vlatter out of engagement with said driven member, means for disengaging said latch, and means independent of saiddriving and driven members for causing said latch to reengage said pawl.

13. In a devicev of the class described, a driving member, a member adapted to be` driven either impulsively or synchronously with said driving member, a normally rotating spring drivably connecting said members, a pawl engageable periodically 'with said driven member to hold the latter during storage of impulse producing energy in said spring, and a spring-pressed plunger engageable with said pawl to normally hold the latter out ofengagement with said driven member,means including a cam for disengaging said plunger in response to deceleration of said driven member,' a spring constantly urging said pawl toward said driven member, and a second spring constantly urging said -cam away from said plunger.

EDWARD B. NOWOSIELSKI. 

